The present invention relates to devices for delivering, infusing, injecting, administering or dispensing a substance, and to methods of making and using such devices. More particularly, it relates to a method for stimulating tissue and to a device for this purpose.
Continuous subcutaneous insulin infusion (CSII) or pump therapy is at present a most effective form of insulin therapy for treatment of insulin-dependent diabetes.
The insulin is not injected in individual doses but is, instead, introduced into the body by a small programmable pump. The pump is located permanently or semi-permanently on the body, not in the body, and insulin is delivered via a catheter with cannula according to a programmed regimen. Insulin catheters are available in different lengths and with different needle sizes and needle materials. The following principle is applied in the administration of insulin: there is a basal supply of insulin, which is output by the pump and covers the non-dietary insulin requirement, and several so-called boluses, that is to say individual dosed releases of insulin, which can be used at meal times and to correct blood sugar values. There is usually just one type of insulin present in these pumps, either standard insulin or insulin analogs.
Pump therapy is a favorable form of insulin therapy because, in contrast to other therapies (ICT, intensive conventional insulin therapy, syringes for basal and bolus therapy, etc.), the basal rate can be more exactly controlled. An insulin pump delivers fast-acting insulin at short, regular intervals in order to achieve a uniform action. The basal rate per hour can be programmed into the pumps. Therefore, pump therapy has become a routine therapy.
In typical insulin pumps, a small motor in the insulin pump conveys the insulin out of a reservoir in the pump, through a catheter and into the subcutaneous fatty tissue, normally in the abdominal region. The pumping speed of the motor, and therefore the quantity of insulin per unit of time, can be programmed according to the patient's needs.
If, in addition to the insulin basal rate, an insulin bolus is to be released, a user can actively obtain insulin in order to lower a raised blood sugar level and/or to obtain insulin for a meal containing carbohydrates. The motor of the pump then conveys additional insulin through the catheter into the subcutaneous fatty tissue.
Such catheters comprise a plastic tube and a cannula, which extends through the skin into the subcutaneous fatty tissue. The cannulas are made, for example, of steel or plastic, for example Teflon. The catheters additionally comprise a main body which is provided on the cannula and which is secured to the skin by means of a sticking plaster or a self-adhesive cover.
In contrast to cannulas, which have to be inserted anew on each occasion, catheters of this kind for insulin therapy can remain in one place for three days, for example, before a new catheter is inserted at another site.
In the abovementioned pump therapy, it is desirable for the insulin kinetics, i.e. the time profile of the insulin concentration in the blood, to proceed as quickly as possible. For this reason, fast-acting insulin analogs are mainly used in pump therapy.
The resorption kinetics of insulin in the body depend on various factors, some of which can be influenced directly by the diabetic. For example, it is known that massaging the injection site accelerates the kinetics. This effect is used by some diabetics when administering boluses, in order to ensure a shorter interval between injecting and eating, or to bring hyperglycaemia as quickly as possible back to the euglycaemic range.
In pump therapy, massaging the injection site is difficult, and sometimes not really possible at all, since the cannula is already inserted and its means of securing does not permit access to the injection site.
Therefore, there is a need in the medical industry to have a device and a method that would facilitate massaging of the infusion site.